The Robinson reference shows this helmet without a plume holder on the crown. However, as displayed in the BM, a holder has been fitted. Also, the helmet is shown with cheek guards fitted, which are not original to this helmet. A cast brow reinforcement is attached at the sides with a single rivet.
Another apparent difference between the photo shown in HRR and the helmet on display is that it is quite clear that there is a punched incription on the neck guard, which does not appear in the photo (nor is it mentioned) in HRR. These punched graffiti read: (a) >.M.VAL..VRS.L.DVLCI [Property of Lucius Dulcius in the century of Marcus Valerius Ursus]; (b) >.MART.L.POSTVMVS [In the century of Martialis, Lucius Postumus]; (c) >.SCR.RVFI [Property of Rufus in the century of Scribonius]; (d) >.MA.AVL.SAFVEI [Property of Aulus Saufeius in the century of Martialis]. Some other names appear to have been deleted. (Note: The symbol '>' - a capital 'C' written backwards - is taken to mean 'century'.)
Patches are sweated on to the sides of the helmet, above the ears. These appear to have been plume holders.
The hinge plates for the cheek guards are each secured in position by a pair of dome-headed rivets.
References:
Robinson, H.R. (1975), “The Armour of Imperial Rome”, (Arms & Armour Press), p.32, No.54
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